Driving type patient platform, control device for driving type patient platform, control program for driving type patient platform, and particle beam therapy system utilizing these items

ABSTRACT

A patient platform for making the position and posture of a diseased site coincide with those established by a treatment plan. Translation units translate a top board in the X, Y and Z directions respectively, in a fixed coordinate system. Rotation units rotate the top board in the θ, φ, and ξ directions respectively. A controller controls the translation units and rotation units, based on desired rotation center point and desired rotation angle. The controller has a rotation drive signal generation unit that generates a signal for moving the top board in a rotating manner from the reference state “a” of the translation units and the rotation units to a desired rotation angle; and a translation drive signal generation unit that generates a signal for translating the translation units so the amount of translation movement, of the desired rotation center point, caused by the rotation movement is a predetermined value.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a particle beam therapy system and aradiation therapy system utilized in the medical and R&D fields andparticularly to a driving type patient platform, a control device forthe driving type patient platform, and a control program for the drivingtype patient platform.

2. Description of the Related Art

To date, with the development of medical apparatuses and the advancementof medicine, medical apparatuses have been sophisticated and there havebeen emerging the types of medical apparatuses, which have not been seenbefore. For example, to date, the treatment through surgery, medicationand/or radiation has been dominant in the cancer treatment; however,recently, much attention has been attracted by a particle beam therapysystem that performs treatment by irradiating a particle beamexemplified by a proton beam or a carbon beam. The greatestcharacteristic of the treatment through a particle beam therapy systemis that it is low-invasive, whereby the after-therapy QOL (Quality ofLife) of a patient can be maintained. At present, particle beam therapysystems are working or under construction at approximately 10 facilitiesin total in Japan; some of the facilities are reportedly treating asmany as 1,000 patients a year.

Accordingly, with regard to a bed, a chair, or the like (hereinafter,referred to as a “patient platform”) on which a patient is situated whenundergoing a particle beam therapy, a function suitable for particlebeam therapy is required; in addition, it leads to the contribution tothe growth of the medical apparatus industry to develop a patientplatform having a function suitable for particle beam therapy so as toproduce a better medical apparatus.

Speaking briefly, a particle beam therapy system irradiates a particlebeam in a pinpoint manner in accordance with the shape of a diseasedsite. For that purpose, it is required that the doctor or engineer(referred to as a “engineer or the like”, hereinafter) who operates theparticle beam therapy system has to perform the work in which, assumingthat the isocenter, which is an irradiation center, is a referenceposition, the position and the posture of the diseased site is made tocoincide with planned values, i.e., the positioning work so that aparticle beam can be irradiated in accordance with the shape of thediseased site. In the positioning work, while the position of a diseasedsite is being monitored by an X-ray image-capturing device, the angleadjustment for a treatment table is implemented in such a way that aparticle beam is irradiated onto the diseased site along a directiondetermined at the stage of making a treatment plan; however, becausethis positioning work takes a long time, it is required to efficientlyperform the positioning work.

In order to realize irradiation onto a patient fixed on the surface of atreatment bed from an arbitrary direction and with an arbitrarydistance, especially, non-conplanar irradiation in which the irradiationdirection is not perpendicular to the patient center axis, there hasbeen proposed a radiation-therapy bed system (refer to Japanese PatentApplication Laid-Open No. 1999-313900). In the radiation-therapy bedsystem, there are inputted patient position data (in an X-Y-Z coordinatesystem) and proton beam radiation angle, which are calculated whentherapy simulation is performed; these data items (position and angle)are coordinate-transformed, as the X-direction, Y-direction, andZ-direction positions of the bed, the i-axis rotation angle (relativeisocentric rotation), the p-axis rotation angle (pitching rotation), ther-axis rotation angle (rolling rotation), and the diseased-site positionof a patient; the respective axes of the bed capture these transformeddata items, as input position data items, and the respective axes aredriven so that the patient diseased site is moved to a desirableposition.

However, in the case where, while the diseased site or the like is beingmonitored by an X-ray image-capturing device, the i-axis, the p-axis,and the r-axis are adjusted, it is normally impossible to dispose thediseased site in such a way as to pass through the rotation center ofeach axis; therefore, the diseased site moves in the X-axis direction,Y-axis direction, or Z-axis direction, or in a direction obtained bycombining these directions. As a result, in some cases, the diseasedsite falls outside the image capturing area of the X-ray image-capturingdevice; thus, in order to prevent the diseased site from falling outsidethe image capturing area, it is required to subtly adjust the X-axis,the Y-axis, and the Z-axis so that the position of the diseased sitedoes not move.

In a conventional radiation-therapy bed system, there is provided sixdegrees of freedom in the driving axes, and by driving each axis, thediseased site of a patient can be moved to a desirable position;however, in the practical positioning work for the diseased site, it isrequired to subtly adjust the X-axis, the Y-axis, and the Z-axis, asdescribed above. Therefore, there has been a problem that thisadjustment work is extremely bothersome to the engineer or the like, andbecause the positioning work takes a long time, the throughput of theparticle beam therapy system cannot be improved.

SUMMARY OF THE INVENTION

The objective of the present invention is to obtain a driving typepatient platform in which there can efficiently be performed thepositioning work for making the position and the posture of a diseasedsite coincide with those established when a treatment plan is generated.

There are provided translation unit that translate the top board in theX direction, the Y direction, and the Z direction, respectively, in afixed coordinate system fixed to an installation place; rotation unitthat rotate the top board in the θ direction around the X axis, the φdirection around the Y axis, and the ξ direction around the Z axis,respectively; and a control device that controls the translation unitand the rotation unit, based on an inputted desired rotation centerpoint and an inputted desired rotation angle. The control device isprovided with a rotation drive signal generation unit that generates arotation drive signal for performing rotation movement of the top boardfrom the reference position states of the translation unit and therotation unit to the desired rotation angle; and a translation drivesignal generation unit that generates a translation drive signal fortranslating the translation unit in such a way that the amount oftranslation movement, of the desired rotation center point, that iscaused by the rotation movement becomes the same as or smaller than apredetermined value.

Based on an inputted desired rotation center point and an inputteddesired rotation angle, a driving type patient platform according to thepresent invention is driven by combining the rotation drive of the topboard and the translation drive performed in such a way that thetranslation movement amount, of the desired rotation center point, thatis produced by rotation-moving the top board to the desired rotationangle is the same as or smaller than a predetermined value, so that thepatient platform can automatically be rotated on a point within apredetermined distance from the desired rotation center point;therefore, there can efficiently be performed the positioning work formaking the position and the posture of a diseased site coincide withthose established when a treatment plan is generated.

The foregoing and other object, features, aspects, and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating a driving typepatient platform (patient platform) according to Embodiment 1 or 2 ofthe present invention;

FIG. 2A and FIG. 2B are charts for explaining that a driving subject isrotation-driven on a desired position;

FIG. 3 is an orthographic three-view of the patient platform in FIG. 1;

FIG. 4A is an orthographic three-view for representing a coordinatesystem in the case where the patient platform in FIG. 1 is a controlsubject;

FIG. 4B is a schematic configuration diagram for representing acoordinate system in the case where the patient platform in FIG. 1 is acontrol subject;

FIG. 5A is an orthographic three-view obtained by adding a coordinatesystem for a rolling rotation member to FIG. 4A and FIG. 4B;

FIG. 5B is a schematic configuration diagram obtained by adding acoordinate system for a rolling rotation member to FIG. 4A and FIG. 4B;

FIG. 6A is an orthographic three-view obtained by adding a coordinatesystem for a pitching rotation member to FIG. 5A and FIG. 5B;

FIG. 6B is a schematic configuration diagram obtained by adding acoordinate system for a pitching rotation member to FIG. 5A and FIG. 5B;

FIG. 7 is a flowchart representing a program according to Embodiment 1or 2;

A set of FIG. 8A and FIG. 8B is a block diagram for explaining thecontrol of the patient platform according to Embodiment 1;

FIG. 9 is a block diagram illustrating a desired position and posturetransformation unit in FIGS. 8A and 8B;

A set of FIG. 10A and FIG. 10B is a block diagram for explaining thecontrol of the patient platform according to Embodiment 2;

FIG. 11 is a view of a patient platform controller according toEmbodiment 3 or 4;

FIG. 12A, FIG. 12B and FIG. 12C are external views of a patient platformoperation terminal according to Embodiment 3 or 4;

A set of FIG. 13A and FIG. 13B is a block diagram for explaining thecontrol of a patient platform according to Embodiment 5;

A set of FIG. 14A and FIG. 14B is another block diagram for explainingthe control of the patient platform according to Embodiment 5; and

FIG. 15 is a configuration diagram illustrating a particle beam therapysystem according to Embodiment 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIG. 1 is a schematic configuration diagram illustrating a driving typepatient platform (patient platform) according to Embodiment 1 of thepresent invention. Based on FIG. 1, the configuration of the patientplatform, which is a control subject, will be explained. A driving typepatient platform (bed type) 1 is an example of control subject inEmbodiment 1. The driving type patient platform 1 is installed on afloor 2. A patient platform configuration member (X-translation member)3 is one of members configuring the patient platform and is driven inthe X direction with respect to the floor 2. A patient platformconfiguration member (Z-translation member) 4 is one of membersconfiguring the patient platform and is driven in the Z direction withrespect to the X-translation member 3. A patient platform configurationmember (Y-translation member) 5 is one of members configuring thepatient platform and is driven in the Y direction with respect to theZ-translation member 4. A patient platform configuration member (yawrotation member) 6 is one of members configuring the patient platformand is driven in a yaw rotation manner with respect to the Y-translationmember 5. A patient platform configuration member (rolling rotationmember) 7 is one of members configuring the patient platform and isdriven in a rolling rotation manner with respect to the yaw rotationmember 6. A patient platform configuration member (pitching rotationmember) 8 is one of members configuring the patient platform and isdriven in a pitching rotation manner with respect to the rollingrotation member 7. The X-translation member 3, the Z-translation member4, and the Y-translation member 5 are translation unit. The yaw rotationmember 6, the rolling rotation member 7, and the pitching rotationmember 8 are rotation unit. The patient platform configuration members 3to 8 are driven by a driving device (unillustrated), based on a controlsignal from a control device 29 (unillustrated).

Next, based on FIG. 2A and FIG. 2B, there will be explained theoperation of “rotation-driving a rotation subject with respect to adesired position”, which is implemented in the present invention. FIG.2A and FIG. 2B are charts for explaining a method of realizing theoperation of rotation-driving a driving subject with respect to adesired position. FIG. 2A is a plan view; FIG. 2B is a bird's eye view.A driving subject 20 signifies a driving subject such as the top boardof a patient platform. A rotation drive center (axis) 21 signifies arotation drive center (axis) in the case where the driving subject 20 isrotation-driven by a rotation driving device such as a motor. A desiredposition 22 is a point (desired rotation center point) for expressing adesired position as an imaginary rotation center such as an isocenter,which is an irradiation reference.

FIG. 2A and FIG. 2B illustrates that the driving subject 20, which is arigid body, is rotated on the rotation drive center (axis) 21 and isconcurrently moved in a translation manner so that the imaginaryrotation center becomes the desired position 22. In Embodiment 1,rotation driving and translation driving are combined in such a way asdescribed above so that the driving subject is moved in a rotationmanner at the desired position.

FIG. 3 is an orthographic three-view of a patient platform according toEmbodiment 1. FIG. 3( a) is a plan view of the patient platform 1; FIG.3( b) is an elevation view of the patient platform 1; FIG. 3( c) is aside view of the patient platform 1. The yaw rotation member 6 is drivenin a yaw rotation manner on a yaw rotation center (axis) 15 with respectto the Y-translation member 5. The rolling rotation member 7 is drivenin a rolling rotation manner on a rolling rotation center (axis) 16 withrespect to the yaw rotation member 6. The pitching rotation member 8 isdriven in a pitching rotation manner on a pitching rotation center 17with respect to the rolling rotation member 7.

Each of FIGS. 4A through 6A is an orthographic three-view forrepresenting a coordinate system in the case where the patient platform1 in FIG. 1 is a control subject in Embodiment 1. FIG. 4A is anorthographic three-view for representing a coordinate system in the casewhere the patient platform is a control subject; FIG. 4B is a schematicconfiguration diagram for representing a coordinate system in the casewhere the patient platform in FIG. 1 is a control subject; FIG. 5A is anorthographic three-view obtained by adding a coordinate system for arolling rotation member to FIG. 4A and FIG. 4B; FIG. 6A is anorthographic three-view obtained by adding a coordinate system for apitching rotation member to FIG. 5A and FIG. 5B; FIG. 6B is a schematicconfiguration diagram obtained by adding a coordinate system for apitching rotation member to FIG. 5A and FIG. 5B. Each of FIGS. 4A(a),5A(a), and 6A(a) is a plan view of the patient platform 1; Each of FIGS.4A(b), 5A(b), and 6A(b) is an elevation view of the patient platform 1;Each of FIGS. 4A(c), 5A(c), and 6A(c) is a side view of the patientplatform 1; Each of FIGS. 4B, 5B, and 6B is a bird's eye view of thepatient platform 1. Based on FIGS. 4A through 6A and FIGS. 4B through6B, the coordinate system in the present invention will be explained.

A coordinate system 10 is a coordinate system O_(fix) (fixed coordinatesystem) fixed in a treatment room. A coordinate system 11 is acoordinate system o₅ fixed to the Y-translation member 5. Therelationship between the coordinate system 10 and the coordinate system11 is uniquely determined by the respective states of the X-translationmember 3, the Z-translation member 4, and the Y-translation member 5,and the coordinate systems can be superimposed on each other throughtranslation movement.

A coordinate system 12 is a coordinate system o₆ fixed to the yawrotation member 6. The relationship between the coordinate system 11 andthe coordinate system 12 is uniquely determined by the state of the yawrotation member 6. When, as illustrated in FIG. 4A and FIG. 4B, thecoordinate system 12 is disposed on the rotation axis of the yawrotation, the direction vector from the origin of the coordinate system11 to the origin of the coordinate system 12 is constant regardless ofthe state of the yaw rotation member 6; thus, the coordinate systems canbe superimposed on each other through translation movement and yawrotation.

A coordinate system 13 is a coordinate system o₇ fixed to the rollingrotation member 7. The relationship between the coordinate system 12 andthe coordinate system 13 is uniquely determined by the state of therolling rotation member 7. When, as illustrated in FIG. 5A and FIG. 5B,the coordinate system 13 is disposed on the rotation axis of the rollingrotation, the direction vector from the origin of the coordinate system12 to the origin of the coordinate system 13 is constant regardless ofthe state of the rolling rotation member 7; thus, the coordinate systemscan be superimposed on each other through translation movement androlling rotation.

A coordinate system 14 is a coordinate system o_(obj) (moving coordinatesystem) fixed to the pitching rotation member 8 (top board). Therelationship between the coordinate system 13 and the coordinate system14 is uniquely determined by the state of the pitching rotation member8. When, as illustrated in FIG. 6A and FIG. 6B, the coordinate system 14is disposed on the rotation axis of the pitching rotation, the directionvector from the origin of the coordinate system 13 to the origin of thecoordinate system 14 is constant regardless of the state of the pitchingrotation member 8; thus, the coordinate systems can be superimposed oneach other through translation movement and pitching rotation.

FIG. 7 is a flowchart representing a program according to Embodiment 1;this program is installed in the control device 29. Based on FIG. 7, theflow of the program will be explained.

In the step S1, initialization is implemented. In the step S1,declaration and definition of variables are performed. In the step S2,reading is implemented. In the step S2, when the state of the patientplatform is a state “a” (reference state), there is read data thatspecifies the respective positions and postures of the patient platformconfiguration members 3 through 8. In the step S3, reading isimplemented. In the step S3, there is read the coordinates P_(fix) (X,Y, Z) of a desired imaginary rotation center point (desired rotationcenter point) P such as an isocenter which is an irradiation reference.

In the step S4, calculation is implemented. In the step S4, when thepatient platform is in the state “a”, the foregoing desired pointP_(fix) (X, Y, Z) in the fixed coordinate system O_(fix) iscoordinate-transformed into coordinates p_(a) (x, y, z) in a “coordinatesystem o_(obj) fixed to the top board”. In the step S5, reading isimplemented. In the step S5, when the state of the patient platform is astate “b”, there is read data that specifies the respective positionsand postures of the patient platform configuration members 3 through 8.The reading of the data corresponds to reading of a desired rotationangle. In the step S6, calculation is implemented. In the step S6,assuming that the patient platform being fixed to the top board has comeinto the state “b” the coordinates p_(a) (x, y, in the “coordinatesystem o_(obj) fixed to the top board” is coordinate-transformed intothe coordinates P_(ab) (X, Y, Z) in the “coordinate system O_(fix) fixedin the treatment room”.

The step S7 is a difference calculation step where a difference iscalculated. In the step S7, there is calculated the difference betweenthe P_(fix) (X, Y, Z) read in the step S3 and the P_(ab) (X, Y, Z)obtained in the step S6. The step S8 is an outputting step whereoutputting is implemented. In the step S8, there is outputted thedifference “P_(ab) (X, Y, Z)−P_(fix) (X, Y, Z)” calculated in the stepS7.

The control device 29 is provided with a rotation drive signalgeneration unit that generates a rotation drive signal for a rotationunit for rotating the patient platform from the state “a” to the state“b”, based on the state “a” of the patient platform that has not beendriven in a rotating manner and the state “b”, of the patient platform,which is a driving target (desired posture), i.e., based on a desiredrotation angle at a time when the patient platform is rotated from thestate “a” to the state “b”; and a translation drive signal generationunit that generates a translation drive signal for compensating thecalculated difference “P_(ab) (X, Y, Z)−P_(fix) (X, Y, Z)” andtranslating the translation unit. The control device 29 generates therotation drive signal and the translation drive signal. With regard tothe details thereof, the contents of each step will be described below.

In the step S1, initialization is implemented; the details thereof willbe described below. In the step S1, there are implemented declaration ofvariables required by the program described in Embodiment 1 anddefinition of parameters and the like that represent geometricinformation on a patient platform. The variables required by the programare, for example, what (referred to as “the state of a patientplatform”, hereinafter) specify the position and the posture of thepatient platform 1, the coordinates of a desired imaginary rotationcenter point, a rotation matrix (a primary transformation matrix), andthe like. The parameters that represent geometric information on thepatient platform 1 denote the position vectors representing thepositions of the origins of the coordinate systems 11 through 14 at atime when all the drive apparatuses for the patient platform 1 are atthe reference positions, i.e., at a time when all the patient platformconfiguration members 3 through 8 are at the reference positions(referred to as “the state of the reference position”, hereinafter).

The state of the patient platform 1 is represented as {x_(s), y_(s),z_(s), θ_(s), φ_(s), ξ_(s)}. In this regard, however, {x_(s), y_(s),z_(s), θ_(s), φ_(s), ξ_(s)} are specified as follows.

The character x_(s) is the x-direction displacement of the X-translationmember 3 with respect to the reference position on the floor 2.

The character y_(s) is the y-direction displacement of the Y-translationmember 5 with respect to the reference position on the Z-translationmember 4.

The character z_(s) is the z-direction displacement of the Z-translationmember 4 with respect to the reference position on the X-translationmember 3.

The character θ_(s) is the pitching-rotation-direction displacementangle of the pitching rotation member 8 with respect to the referenceposition on the rolling rotation member 7.

The character φ_(s) is the rolling-rotation-direction displacement angleof the rolling rotation member 7 with respect to the reference positionon the yaw rotation member 6.

The character ξ_(s) is the yaw-rotation-direction displacement angle ofthe yaw rotation member 6 with respect to the reference position on theY-translation member 5.

The coordinates of the desired imaginary rotation center point P isrepresented as P_(fix) (X, Y, Z). The rotation matrixes for pitchingrotation, rolling rotation, and yaw rotation are represented as theequations (1) through (3), respectively.

$\begin{matrix}{{R_{x}(\theta)} = \begin{bmatrix}1 & 0 & 0 \\0 & {\cos\;\theta} & {{- \sin}\;\theta} \\0 & {\sin\;\theta} & {\cos\;\theta}\end{bmatrix}} & (1) \\{{R_{y}(\phi)} = \begin{bmatrix}{\cos\;\phi} & 0 & {\sin\;\phi} \\0 & 1 & 0 \\{{- \sin}\;\phi} & 0 & {\cos\;\phi}\end{bmatrix}} & (2) \\{{R_{z}(\xi)} = \begin{bmatrix}{\cos\;\xi} & {{- \sin}\;\xi} & 0 \\{\sin\;\xi} & {\cos\;\xi} & 0 \\0 & 0 & 1\end{bmatrix}} & (3)\end{matrix}$

The parameters that represent geometric information on the patientplatform in the state of the reference position are vectors that specifythe positions of the origins of the coordinate systems 11 through 14,and are expressed as the equations (4) through (7).

$\begin{matrix}{\left( {o_{5} - O_{fix}} \right) = \begin{bmatrix}X_{5} \\Y_{5} \\Z_{5}\end{bmatrix}} & (4)\end{matrix}$where (o_(s)−O_(fix)) is the position of the origin of the coordinatesystem 11 viewed from the fixed coordinate system.

$\begin{matrix}{\left( {o_{6} - O_{fix}} \right) = \begin{bmatrix}X_{6} \\Y_{6} \\Z_{6}\end{bmatrix}} & (5)\end{matrix}$where (o₆−O_(fix)) is the position of the origin of the coordinatesystem 12 viewed from the fixed coordinate system.

$\begin{matrix}{\left( {o_{7} - O_{fix}} \right) = \begin{bmatrix}X_{7} \\Y_{7} \\Z_{7}\end{bmatrix}} & (6)\end{matrix}$where (o₇−O_(fix)) is the position of the origin of the coordinatesystem 13 viewed from the fixed coordinate system.

$\begin{matrix}{\left( {o_{obj} - O_{fix}} \right) = \begin{bmatrix}X_{obj} \\Y_{obj} \\Z_{obj}\end{bmatrix}} & (7)\end{matrix}$where (o_(obj)−O_(fix)) is the position of the origin of the coordinatesystem 14 viewed from the fixed coordinate system.

In the step S2, reading is implemented; the details thereof will bedescribed below. In the step S2, when the state of the patient platformis the state “a”, there is read data that specifies the respectivepositions and postures of the patient platform configuration members 3through 8. The state “a” denotes the state of the patient platform at atime when the desired rotation center point P is set. The variables thatspecify the state of the patient platform are as described in the detailof the step S1; thus, specific values are substituted for the variables.The state “a” of the patient platform 1 is represented as {x_(a), y_(a),z_(a), θ_(a), φ_(a), ξ_(a)}.

In the step S3, reading is implemented; the details thereof will bedescribed below. In the step S3, there is read the coordinates P_(fix)(X, Y, Z) of a desired imaginary rotation center point P such as anisocenter which is an irradiation reference. In general, the coordinatesP_(fix) (X, Y, Z) of the desired imaginary rotation center point P isconstant during a certain series of work; therefore, only when requiredto be changed, the coordinates P_(fix) (X, Y, Z) is read and overwrittenon the earlier one.

In the step S4, calculation is implemented; the details thereof will bedescribed below. In the step S4, when the patient platform is in thestate “a”, the foregoing desired point P_(fix) (X, Y, Z) in the fixedcoordinate system O_(fix) is coordinate-transformed into coordinatesp_(a) (x, y, z) in a “coordinate system o_(obj) fixed to the top board”.

At first, based on FIG. 4A and FIG. 4B, the relationship between thecoordinate system 10 and the coordinate system 11 will be explained. Asdescribed in the detail of the step S1, in the state of the referenceposition, the coordinates of the origin of the coordinate system 11 isrepresented as the equation (4) as viewed from the fixed coordinatesystem (i.e., the coordinate system 10). In this situation, the patientplatform is in the state “a”; thus, the coordinates of the origin of thecoordinate system 11 is represented as follows, as viewed from the fixedcoordinate system (i.e., the coordinate system 10).

$\begin{matrix}{\left. \left( {o_{5} - O_{fix}} \right) \right|_{{state}\mspace{14mu} a} = {\begin{bmatrix}X_{5} \\Y_{5} \\Z_{5}\end{bmatrix} + \begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix}}} & (8)\end{matrix}$

In other words, when returned to the negative direction by the foregoingdirection vector, the coordinate system 11 is superimposed on thecoordinate system 10. Accordingly, the coordinate transformation fromthe coordinate system 11 into the fixed coordinate system (i.e., thefixed coordinate system 10) can be obtained by the following equation.

$\begin{matrix}\begin{matrix}{Q_{fix} = \left. \left( {o_{5} - O_{fix}} \right) \middle| {}_{{state}\mspace{14mu} a}{+ q_{5}} \right.} \\{= {\begin{bmatrix}X_{5} \\Y_{5} \\Z_{5}\end{bmatrix} + \begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} + q_{5}}}\end{matrix} & (9)\end{matrix}$

In this regard, however, Q_(fix) is an arbitrary point q represented bythe fixed coordinate system. In addition, q₅ is the arbitrary point qrepresented by the coordinate system 11 fixed to the Y-translationmember 5.

Next, based on FIG. 4A and FIG. 4B, the relationship between thecoordinate system 11 and the coordinate system 12 will be explained. Thearbitrary point q viewed from the coordinate system 12 coincides withthe point q viewed from the coordinate system 11 when, at first,translation movement is performed from the origin of the coordinatesystem 11 to the origin of the coordinate system 12 and then there isperformed yaw rotation by ξ, which is the displacement angle of thecoordinate system 12 with respect to the coordinate system 11. That isto say, the relationship is represented by the following equation.

$\begin{matrix}{q_{5} = {\begin{bmatrix}{X_{6} - X_{5}} \\{Y_{6} - Y_{5}} \\{Z_{6} - Z_{5}}\end{bmatrix} + {{R_{z}(\xi)}q_{6}}}} & (10)\end{matrix}$

In this regard, however, q₆ is the arbitrary point q represented by thecoordinate system 12 fixed to the yaw rotation member 6.

Similarly, based on FIG. 5A and FIG. 5B, the relationship between thecoordinate system 12 and the coordinate system 13 will be explained. Thearbitrary point q viewed from the coordinate system 13 coincides withthe point q viewed from the coordinate system 12 when, at first,translation movement is performed from the origin of the coordinatesystem 12 to the origin of the coordinate system 13 and then there isperformed rolling rotation by φ, which is the displacement angle of thecoordinate system 13 with respect to the coordinate system 12. That isto say, the relationship is represented by the following equation.

$\begin{matrix}{q_{6} = {\begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix} + {{R_{y}(\phi)}q_{7}}}} & (11)\end{matrix}$

In this regard, however, q₇ is the arbitrary point q represented by thecoordinate system 13 fixed to the rolling rotation member 7.

In the last place, based on FIG. 6A and FIG. 6B, the relationshipbetween the coordinate system 13 and the coordinate system 14 will beexplained. The arbitrary point q viewed from the coordinate system 14coincides with the point q viewed from the coordinate system 13 when, atfirst, translation movement is performed from the origin of thecoordinate system 13 to the origin of the coordinate system 14 and thenthere is performed pitching rotation by θ, which is the displacementangle of the coordinate system 14 with respect to the coordinate system13. That is to say, the relationship is represented by the followingequation.

$\begin{matrix}{q_{7} = {\begin{bmatrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{bmatrix} + {{R_{x}(\theta)}q_{obj}}}} & (12)\end{matrix}$

In this regard, however, q_(obj) is the arbitrary point q represented bythe coordinate system 14 fixed to the pitching rotation member 8 (topboard).

By rearranging the equations (9) through (12), there can be performedcoordinate transformation from “the coordinate system o_(obj) fixed tothe top board” into “the coordinate system O_(fix) fixed to thetreatment room”, when the patient platform is in the state “a”. As aresult, the equation (13) is obtained.

$\begin{matrix}{Q_{fix} = {\begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} + \begin{bmatrix}X_{6} \\Y_{6} \\Z_{6\;}\end{bmatrix} + {{R_{z}(\xi)}\left\{ {\begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix} + {{R_{y}(\phi)}\left( {\begin{bmatrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{bmatrix} + {{R_{x}(\theta)}q_{obj}}} \right)}} \right\}}}} & (13)\end{matrix}$

The equation (13) is a coordinate transformation unit C2 (a secondcoordinate transformation unit) for performing transformation of thecoordinate system from “the coordinate system o_(obj) fixed to the topboard” (moving coordinate system) into “the coordinate system O_(fix)fixed to the treatment room” (fixed coordinate system).

By modifying the equation (13), there can be obtained coordinatetransformation from “the coordinate system O_(fix) fixed to thetreatment room” (fixed coordinate system) into “the coordinate systemo_(obj) fixed to the top board” (moving coordinate system).

$\begin{matrix}\begin{matrix}{q_{obj} = {{R_{x}(\theta)}^{- 1}\left\{ {{R_{y}(\phi)}^{- 1}\left\{ {{{R_{z}(\xi)}^{- 1}\left( {Q_{fix} - \begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} - \begin{bmatrix}X_{6} \\Y_{6} \\Z_{6}\end{bmatrix}} \right)} -} \right.} \right.}} \\\left. {\left. \begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix} \right\} - \begin{bmatrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{bmatrix}} \right\} \\{= {{R_{x}\left( {- \theta} \right)}\left\{ {{R_{y}\left( {- \phi} \right)}\left\{ {{{R_{z}\left( {- \xi} \right)}\left( {Q_{fix} - \begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} - \begin{bmatrix}X_{6} \\Y_{6} \\Z_{6}\end{bmatrix}} \right)} -} \right.} \right.}} \\\left. {\left. \begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix} \right\} - \begin{bmatrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{bmatrix}} \right\}\end{matrix} & (14)\end{matrix}$

The equation (14) is a coordinate transformation unit C1 (a firstcoordinate transformation unit) for performing transformation of thecoordinate system from “the coordinate system O_(fix) fixed to thetreatment room” (fixed coordinate system) into “the coordinate systemo_(obj) fixed to the top board” (moving coordinate system).

Accordingly, in the step S4, by utilizing the coordinate transformationunit C1, the foregoing desired point P_(fix) (X, Y, Z) in the fixedcoordinate system O_(fix) at a time when the patient platform 1 is inthe state “a” is coordinate-transformed into coordinates p_(a) (x, y, z)in a “coordinate system o_(obj) fixed to the top board”. Specifically,in the equation (14), p_(a) is substituted for q_(obj), which is thearbitrary point q represented by the coordinate system 14 fixed to thepitching rotation member 8, the desired point P_(fix) is substituted forQ_(fix), which is the arbitrary point q represented by the fixedcoordinate system, and θ_(a), φ_(a), and ξ_(a), which are displacementangles at a time when the patient platform is in the state “a”, aresubstituted for the displacement angles θ, φ, and ξ. In the step S4, theequation (15) is obtained.

$\begin{matrix}{p_{a} = {{R_{x}\left( {- \theta_{a}} \right)}\left\{ {{R_{y}\left( {- \phi_{a}} \right)}\left\{ {{{R_{z}\left( {- \xi_{a}} \right)}\left( {P_{fix} - \begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} - \left. \quad\begin{bmatrix}\begin{matrix}X_{6} \\Y_{6}\end{matrix} \\Z_{6}\end{bmatrix} \right) - \begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix}} \right\}} - \left\lbrack \begin{matrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{matrix} \right\rbrack} \right\}} \right.}} & (15)\end{matrix}$

In the step S5, reading is implemented; the details thereof will bedescribed below. In the step S5, when the patient platform 1 is in thestate “b”, there is read data that specifies the respective positionsand postures of the patient platform configuration members 3 through 8.The state “b” denotes, for example, the target posture of the patientplatform 1 to be achieved. The desired rotation angle is given as theangle of the state “b”, i.e., as an absolute angle. The translationposition of the patient platform 1 is uniquely determined in such a wayas to be the desired imaginary rotation center point; thus, in the stepS5, any value may be substituted. For the sake of simplicity, the valueat a time when the patient platform 1 is in the state “a” is left as itis.

The state “b” of the patient platform 1 is represented as {x_(a), y_(a),z_(a), θ_(b), φ_(b), ξ_(b)}.

In the step S6, calculation is implemented; the details thereof will bedescribed below. In the step S6, assuming that the patient platform 1being fixed to the top board 8 has come into the state “b”, thecoordinates p_(a) (x, y, z) in the “coordinate system o_(obj) fixed tothe top board” is coordinate-transformed into the coordinates P_(ab) (X,Y, Z) in the “coordinate system O_(fix) fixed in the treatment room”.Specifically, in the step S6, assuming that the patient platform 1 beingfixed to the top board 8 has come into the state “b”, the coordinatesp_(a) (x, Y, z) in the “coordinate system o_(obj) fixed to the topboard” is coordinate-transformed by use of the coordinate transformationunit C2 into the coordinates P_(ab) (X, Y, Z) in the “coordinate systemO_(fix) fixed in the treatment room”. In the step S6, the equation (16)is implemented.

$\begin{matrix}{P_{ab} = {\begin{bmatrix}x_{a} \\y_{a} \\z_{a}\end{bmatrix} + \begin{bmatrix}X_{6} \\Y_{6} \\Z_{6}\end{bmatrix} + {{R_{z}\left( \xi_{b} \right)}\left\{ {\begin{bmatrix}{X_{7} - X_{6}} \\{Y_{7} - Y_{6}} \\{Z_{7} - Z_{6}}\end{bmatrix} + {{R_{y}\left( \phi_{b} \right)}\left( {\begin{bmatrix}{X_{obj} - X_{7}} \\{Y_{obj} - Y_{7}} \\{Z_{obj} - Z_{7}}\end{bmatrix} + {{R_{x}\left( \theta_{b} \right)}p_{a}}} \right)}} \right\}}}} & (16)\end{matrix}$

The step S7 is a difference calculation step where a difference iscalculated; the details thereof will be described below. In the step S7,there is calculated the difference between the P_(fix) (X, Y, Z) read inthe step S3 and the P_(ab) (X, Y, Z) obtained in the step S6. In thestep S7, the equation (17) is obtained.ΔP=P _(ab) −P _(fix)  (17)

The step S8 is an outputting step where outputting is implemented; thedetails thereof will be described below. In the step S8, ΔP(=P_(ab)−P_(fix)) calculated in the step S7 is outputted, as acompensation amount, to the respective controllers of the drivingdevices for the patient platform configuration members 3 through 5. Thiscompensation amount becomes the translation drive signal. ΔP(=P_(ab)−P_(fix)) physically denotes the direction vector between thepoint P at a time when the patient platform 1 is in the state “a” andthe point P at a time when the patient platform 1 is in the state “b”,i.e., the vector amount obtained from the movement of the point P.Accordingly, by compensating the state “b” by ΔP (=P_(ab)−P_(fix))calculated in the step S7, the rotation center can be the desired pointP as the posture of the patient platform 1 is kept to be in the state“b”. As a result, the compensated state “b′” of the patient platform 1can be expressed as follows.{x _(a) −ΔP _(x) ,y _(a) −ΔP _(y) ,z _(a) −ΔP _(z),θ_(b),φ_(b),ξ_(b)}where ΔP_(x), ΔP_(y), and ΔP_(z) denote the x, y, and z components ofΔP, respectively.

The program represented in the flowchart in FIG. 7 is integrated in acontroller 34. The method in which the controller 34 controls thepatient platform 1 will be explained. A set of FIG. 8A and FIG. 8B is ablock diagram for explaining the control of the patient platform 1according to Embodiment 1; FIG. 9 is a block diagram illustrating adesired position and posture transformation unit. The controller 34 (34a) has four input units 65 a, 65 b, 65 c, and 65 d, a desired positionand posture transformation unit 60, a mode switch 66, and an output unit67. The mode switch 66 performs switching between desired position andposture {x*, y*, z*, θ*, φ*, ξ*} from the input unit 65 a and desiredposition and posture {x*, y*, z*, θ*, φ*, ξ*} from the desired positionand posture transformation unit 60. In the case of the mode 1, a commandsignal is outputted to the driving device for the patient platform 1,based on the desired position and posture from the input unit 65 a; inthe case of the mode 2, a command signal is outputted to the drivingdevice for the patient platform 1, based on the desired position andposture from the desired position and posture transformation unit 60.The mode 1 has been implemented to date; in the mode 2, the flowchart inFIG. 7 is implemented. The characters with “*” denotes target valuesthat do not change with time, and so are the characters with “*” amongcharacters explained hereinafter.

The state “a” of the patient platform and the coordinates P_(fix) (X, Y,Z) of the desired rotation center point read in the steps S2 and S3 areinputted to the input units 65 d and 65 c, respectively. As describedabove, the state “a” is the state of the patient platform 1 at a timewhen the coordinates P_(fix) of the desired rotation center point isinputted. The target posture (the state “b”) of the patient platformread in the steps S5 is inputted to the input unit 65 b. The desiredposition and posture transformation unit 60 implements the steps S6through S8 so as to calculate the desired position and posture (state“b′”) {x_(a)−ΔP_(x), y_(a)−ΔP_(y), z_(a)−ΔP_(z), θ_(b), φ_(b), ξ_(b)}.Based on the compensated desired position and posture {x*, y*, z*, θ*,φ*, ξ*} in the state “b′” of the patient platform 1, the output unit 67outputs the command signals sig1 a through sig1 f to driving devices 35through 40 (refer to FIG. 11) for six axes. A sensor, such as anencoder, for detecting the rotation angle is disposed in each of thedriving devices (motors) 35 through 40. In FIGS. 8A and 8B, the motorsand encoders for six axes are designated as motor/encoders 69 a through69 f. In general, the driving devices 35 through 40 are controlled bydrivers. The driving devices 35 through 40 are controlled in such a waythat the driving devices (motors) 35 through 40 are driven by drivesignals sig2 a through sig2 f, the present statuses x(t) through ξ(t) ofthe driving devices (motors) 35 through 40 are detected by encoders orthe like, and detection signals sig3 a through sig3 f from the encodersor the like are fed back to motor drivers 68 a through 68 f.

The command signal sig1 a, the drive signal sig2 a, the detection signalsig3 a, the present state x(t), the driver 68 a, and the motor/encoder69 a are related to the driving device (X translation motor) 35. Thecommand signal sig1 b, the drive signal sig2 b, the detection signalsig3 b, the present state y(t), the driver 68 b, and the motor/encoder69 b are related to the driving device (Y translation motor) 36. Thecommand signal sig1 c, the drive signal sig2 c, the detection signalsig3 c, the present state z(t), the driver 68 c, and the motor/encoder69 c are related to the driving device (Z translation motor) 37. Thecommand signal sig1 d, the drive signal sig2 d, the detection signalsig3 d, the present state θ(t), the driver 68 d, and the motor/encoder69 d are related to the driving device (yaw rotation motor) 38. Thecommand signal sig1 e, the drive signal sig2 e, the detection signalsig3 e, the present state φ(t), the driver 68 e, and the motor/encoder69 e are related to the driving device (rolling rotation motor) 39. Thecommand signal sig1 f, the drive signal sig2 f, the detection signalsig3 f, the present state ξ(t), the driver 68 f, and the motor/encoder69 f are related to the driving device (pitching rotation motor) 40.

The operation of the desired position and posture transformation unit 60will be explained with reference to FIG. 9. The desired position andposture transformation unit 60 has the first coordinate transformationunit C1 (61), the second coordinate transformation unit C2 (62), acalculation unit 63, and a desired position and posture calculation unit64. The first coordinate transformation unit C1 (61) implements the stepS4. In the state “a” set by its program variables 71, the firstcoordinate transformation unit C1 (61) transforms the coordinatesP_(fix) (X, Y, Z) of the desired rotation center point in a fixedcoordinate system into the coordinates p_(a) (x, y, z) in a movingcoordinate system.

The second coordinate transformation unit C2 (62) implements the stepS6. Assuming that the state of the patient platform is in the state “b”(target position {x_(a), y_(a), z_(a)}, target posture {θ_(b), φ_(b),ξ_(b)}) set by its program variables 72, the second coordinatetransformation unit C2 (62) transforms the coordinates p_(a) (x, y, z)of the desired rotation center point in a moving coordinate system intothe coordinates P_(ab) (X, Y, Z) in a fixed coordinate system. Thecalculation unit 63 implements the step S7 so as to calculate ΔP(=P_(ab)−P_(fix)). The desired position and posture transformation unit64 implements the step S8 so as to calculate the desired position andposture {x*, y*, z*, θ*, φ*, ξ*} in the compensated state “b” of thepatient platform 1, i.e., {x_(a)−ΔP_(x), y_(a)−ΔP_(y), z_(a)−ΔP_(z),θ_(b), φP_(b), ξ_(b)}.

There are conceivable roughly three methods to provide the state “b”.They are a regulator type, a servo system type, and a JOG drive type.The regulator type method provides the target posture to be eventuallyobtained. In this case, the state “b” does not change during a series ofoperations. The servo system type method instructs halfway passingpoints (postures) as well. In this case, the state “b” changes inaccordance with a predetermined sequence. The JOG drive type methodperforms instruction through a JOG lever. In this case, the state “b”changes at a constant speed when the JOG lever is thrown. The JOGdriving will be described in detail in Embodiment 3.

The patient platform 1 in Embodiment 1 can be rotated at a desiredpoint, by combining rotation drive and translation drive in which thereis compensated the difference between the coordinates of an arbitrarypoint (the desired point P) in the state “a” and the coordinates of anarbitrary point in the state “b”, based on the desired point P (thedesired rotation center point P) and the desired rotation angle. By onlyperforming control inputting for implementing rotation drive, thepatient platform 1 can be rotated on a desired point P; therefore, therecan efficiently be performed the positioning work for making theposition and the posture of a diseased site coincide with thoseestablished when a treatment plan is generated.

By utilizing the isocenter, which is the irradiation center of aparticle beam therapy system, as the desired point P of the patientplatform 1, the movement of the patient platform 1 can be made compact.Because the movement of the patient platform 1 becomes compact, theinterference between the patient platform 1 or a patient fixed on thepatient platform and apparatuses other than the patient platform 1 ofthe particle beam therapy system can more readily be prevented in thepositioning work for making the position of the patient platformcoincide with the position established in the treatment plan.

Regardless of the type of a patient platform such as a bed or a chair,the program, according to Embodiment 1, for implementing the positioningmethod for the patient platform 1 can be applied even to an alreadyinstalled patient platform, without hardware modification or additionalconstruction work being carried out. As described above, due to thescalability, there can be performed the control of diseased-siterotation on the desired point P; thus, there can readily be performedthe positioning work where the position and the posture of a diseasedsite is made to coincide with those established when the treatment planis generated. As a result, the time for preparing treatment canconsiderably be reduced.

The foregoing explanation has been made with an example where thedesired rotation angle is given as the angle of the state “b”, i.e., anabsolute angle; however, it may also be allowed that the desiredrotation angle is given as the relative angle between the state “a” andthe state “b”. In both cases, the posture of a diseased site can be madeto coincide with the posture given by the desired rotation angle.

As described above, in the driving type patient platform 1 according toEmbodiment 1, there are provided the translation unit 3, 4, and 5 thattranslate the top board 8 in the X direction, the Y direction, and the Zdirection, respectively, in the fixed coordinate system 10 fixed to theinstallation place; the rotation unit 6, 7, and 8 that rotate the topboard 8 in the θ direction around the X axis, the φ direction around theY axis, and the ξ direction around the Z axis, respectively; and thecontrol device that controls the translation unit 3, 4, and the rotationunit 6, 7, and 8, based on an inputted desired rotation center point Pand an inputted desired rotation angle. The control device is providedwith the rotation drive signal generation unit that generates therotation drive signal for moving the top board 8 in a rotating mannerfrom the reference state “a” of the translation unit 3, 4, and 5 and therotation unit 6, 7, and 8 to a desired rotation angle; and thetranslation drive signal generation unit that generates the translationdrive signal for translating the translation unit 3, 4, and 5 in such away that there is compensated the amount of translation movement, of thedesired rotation center point P, that is caused by the rotationmovement. As a result, there can be performed the control ofdiseased-site rotation on the desired rotation center point P;therefore, there can efficiently be performed the positioning work formaking the position and the posture of a diseased site coincide withthose established when a treatment plan is generated.

Embodiment 2

In Embodiment 1, the foregoing explanation has been made with an examplewhere there is performed the control of diseased-site rotation on thedesired rotation center point P; however, even in the case where adiseased site is rotated within a predetermined distance from thedesired rotation center point P, i.e., the diseased site is rotated at adesired rotation angle and the desired rotation center point P in themoving coordinate system is moved by as far as a predetermined distance,as viewed from the fixed coordinate system, there can efficiently beperformed the positioning work for making the position and the postureof a diseased site coincide with those established when a treatment planis generated. As described above, with regard to the positioning workfor a diseased site, it is only necessary that, during the work, thediseased site is within the image capturing area of the X-rayimage-capturing device; therefore, even in the case where the drivingdevice for the patient platform 1 is controlled by the command signalssig1 a through sig1 f based on the desired position and posture {x*, y*,z*, θ*, φ*, ξ*} in which there is set a positional deviation (coordinatedeviation) or an offset due to the error in the driving device for thepatient platform 1, by rotating the driving subject 20 (the top board 8)in such a way that the rotation position is within a predetermineddistance from the desired rotation center point P, there can efficientlybe performed the positioning work for making the position and theposture of a diseased site coincide with those established when atreatment plan is generated. The predetermined distance is the distancebetween the outer circumference of the image capturing area and thediseased site; the predetermined value of the translation movementamount is this predetermined distance.

In the case where the driving device is controlled by the commandsignals sig1 a through sig1 f with which an offset is set, the followingeffects are demonstrated. For example, in the case where a diseased siteappears at the bottom of the captured image of the X-ray image-capturingdevice, by rotating the posture of the diseased site on the desiredrotation center point P, the whole diseased site can be moved to thecenter of the captured image. In such a way as described above, it ismade possible to move the diseased site to a desired position in ashorter time than that in the case where the diseased site is moved tothe center of the captured image and then is rotated on the desiredrotation center point P.

In the case where a positional deviation (coordinate deviation) iscaused by an error in the driving device for the patient platform 1, thesame flow as that from the step S1 through S8 in FIG. 7 is applied.There will be explained the case where the driving device is controlledby the command signals sig1 a through sig1 f with which an offset isset. A set of FIG. 10A and FIG. 10B is a block diagram for explainingthe control of the patient platform 1 according to Embodiment 2. A setof FIG. 10A and FIG. 10B is different from a set of FIG. 8A and FIG. 8Bin Embodiment 1 in that an input unit 65 e and a calculation unit 70 areadded to the controller 34 (34 b), and the desired position and posture{x*, y*, z*, θ*, φ*, ξ*} is generated by adding {Δx_(p)*, Δy_(p)*,Δz_(p)*, 0, 0, 0} to the desired position and posture calculated by thedesired position and posture transformation unit 60.

The flow from the step S1 through the step S8 in FIG. 7 is similarlyapplied; after that, the step S9 is implemented. In the step S9, atranslation movement amount {Δx_(p)*, Δy_(p)*, Δz_(p)*}, which is thedifference P_(c) (X, Y, Z) that is the same as or smaller than thepredetermined value and obtained from the coordinates P_(fix) (X, Y, Z)of the desired rotation center point, is added to the desired positionand posture {x_(a)−ΔP_(x), y_(a)−ΔP_(y), z_(a)−ΔP_(z), θ_(b), φ_(b),ξ_(b)} calculated in the step S8. The translation movement amount{Δx_(p)*, Δy_(p)*, Δz_(p)*} is inputted to the input unit 65 e. Thecalculation unit 70 generates a desired position and posture {x*, y*,z*, θ*, φ*, ξ*} by adding the translation movement amount {Δx_(p)*,Δy_(p)*, Δz_(p)*} to the desired position and posture {x_(a)−ΔP_(x),y_(a)−ΔP_(y), z_(a)−ΔP_(z), θ_(b), φ_(b), ξ_(b)} calculated by thedesired position and posture transformation unit 60. Based on thegenerated desired position and posture {x*, y*, z*, θ*, φ*, ξ*}, theoutput unit 67 outputs the command signals sig1 a through sig1 f todriving devices 35 through 40 (refer to FIG. 11) for six axes.

As described above, the compensation amount for the controller of thedriving devices 35 through 40 for the patient platform configurationmembers 3 through 5 becomes P_(ab) (X, Y, Z)−P_(fix) (X, Y, Z)+P_(c) (X,Y, Z). The controller 34 (34 b) generates the rotation drive signal forthe rotation unit, based on the desired rotation angle for rotating thepatient platform from the state “a”, which is the state prior torotation driving, to the state “b”, which is the driving target (desiredposture), and generates the translation drive signal for translating thetranslation unit, by performing compensation of the difference value(P_(ab) (X, Y, Z)−P_(fix) (X, Y, Z)) calculated in the step S7 in such away that the translation movement amount becomes the same as or smallerthan the predetermined value.

In some cases, rotating a diseased site on a point that is within apredetermined distance from the desired rotation center point P iseventually equivalent to rotating the diseased site on another rotationcenter point (an imaginary rotation center point). This will beexplained below. It is assumed that the coordinate represented by aone-coordinate system is q₁, the coordinates represented by atwo-coordinate system is q₂, and the translation after θ rotation is “a”(vector). The one-coordinate system and the two-coordinate system are inthe relationship in which, when the one-coordinate system is θ-rotatedand then “a”-translated, the one-coordinate system and thetwo-coordinate system are superimposed on each other; thus, the equation(18) is given.q ₁ =R(θ)q ₂ +a  (18)where R(θ) is a rotation matrix.

When an imaginary rotation center point, which is a fixed point, exists,both a one-coordinate system and a two-coordinate system can berepresented with the same coordinates; thus, the coordinates q_(fix) ofthe fixed point can be obtained as follows. By substituting q_(fix) forq₁ and q₂ of the equation (18) and rearranging it, the equation (19) isobtained.(I−R(θ))q _(fix) =a  (19)where I is a unit matrix.

In the case where the inverse matrix (I−R(θ))⁻¹ of (I−R(θ)) exists, thecoordinates q_(fix) of the fixed point can be represented as theequation (20).q _(fix)=(I−R(θ))⁻¹ a  (20)

For example, in the case where the patient platform is rotated on the Zaxis as a center axis and is translated in the Z axis, (I−R(θ))⁻¹ doesnot exists; therefore, the coordinates q_(fix) of the fixed point cannotbe obtained. However, only when rotation and translation are limited ona two-dimensional plane and the rotation angle is not “0”, the fixedpoint exists. In the case where the fixed point exists, the diseasedsite can be rotated on an imaginary rotation center point.

Based on the desired rotation center point P and the desired rotationangle, the patient platform 1 in Embodiment 2 is driven by combining therotation drive of the top board 8 and the translation drive performed insuch a way that the translation movement amount, of the desired rotationcenter point P, that is produced by rotation-moving the top board 8 tothe desired rotation angle is the same as or smaller than apredetermined value, so that the patient platform 1 can automatically berotated on a point within a predetermined distance from the desiredrotation center point P. As a result, there can efficiently be performedthe positioning work for making the position and the posture of adiseased site coincide with those established when a treatment plan isgenerated.

As is the case with Embodiment 1, regardless of the type of a patientplatform such as a bed or a chair, the program, according to Embodiment2, for implementing the positioning method for the patient platform 1can be applied even to an already installed patient platform, withouthardware modification or additional construction work being carried out.As described above, because of the scalability, the patient platform 1can readily and automatically be rotated on a point within apredetermined distance from the desired rotation center point P.Therefore, there can readily be performed the positioning work formaking the position and the posture of a diseased site coincide withthose established when a treatment plan is generated. As a result, thetime for preparing treatment can considerably be reduced.

As described above, in the driving type patient platform 1 according toEmbodiment 2, there are provided the translation unit 3, 4, and 5 thattranslate the top board 8 in the X direction, the Y direction, and the Zdirection, respectively, in the fixed coordinate system 10 fixed to theinstallation place; the rotation unit 6, 7, and 8 that rotate the topboard 8 in the θ direction around the X axis, the φ direction around theY axis, and the ξ direction around the Z axis, respectively; and thecontrol device that controls the translation unit 3, 4, and the rotationunit 6, 7, and 8, based on an inputted desired rotation center point Pand an inputted desired rotation angle. The control device is providedwith the rotation drive signal generation unit that generates therotation drive signal for moving the top board 8 in a rotating mannerfrom the reference state “a” of the translation unit 3, 4, and 5 and therotation unit 6, 7, and 8 to a desired rotation angle; and thetranslation drive signal generation unit that generates the translationdrive signal for translating the translation unit 3, 4, and 5 in such away that the amount of translation movement, of the desired rotationcenter point P, that is caused by the rotation movement becomes the sameas or smaller than a predetermined value. As a result, the patientplatform 1 can automatically be rotated on a point within apredetermined distance from the desired rotation center point P, andthere can efficiently be performed the positioning work for making theposition and the posture of a diseased site coincide with thoseestablished when a treatment plan is generated.

Embodiment 3

Embodiment 3 of the present invention is a patient platform providedwith a patient platform controller, which is a control device in whichthe program described in Embodiment 1 is integrated. To date, a patientplatform controller has been provided with a suspended patient platformoperation terminal, i.e., a so-called pendant-type patient platformoperation terminal.

FIG. 11 is a view illustrating a patient platform controller accordingto Embodiment 3; FIG. 12A, FIG. 12B and FIG. 12C are external views of apendant-type patient platform operation terminal according to Embodiment3. FIG. 12A is a bird's eye view; FIG. 12B is an elevation view; FIG.12C is a cross-sectional view. With reference to FIGS. 11, 12A, 12B and12C, there will be explained a patient platform controller according toEmbodiment 3 of the present invention.

The patient platform controller 29 includes a patient platform operationterminal 30 and a controller 34. Signal information manipulated by meansof the patient platform operation terminal 30 is inputted to thecontroller 34. The program described in Embodiment 1 is integrated inthe controller 34. The controller 34 outputs control signals to thedriving devices 35 through 40 that drive the patient platformconfiguration members 3 through 8. The driving device (X translationmotor) 35 drives the patient platform configuration member(X-translation member) 3. The driving device (Y translation motor) 36drives the patient platform configuration member (Y-translation member)5. The driving device (Z translation motor) 37 drives the patientplatform configuration member (Z-translation member) 4. The drivingdevice (yaw rotation motor) 38 drives the patient platform configurationmember (yaw rotation member) 6. The driving device (rolling rotationmotor) 39 drives the patient platform configuration member (rollingrotation member) 7. The driving device (pitching rotation motor) 40drives the patient platform configuration member (pitching rotationmember) 8.

The patient platform operation terminal 30 is a pendant-type mobileoperation terminal for the patient platform 1. The patient platformoperation terminal 30 controls the position and the posture of thepatient platform 1. An emergency stop button 31 is a stop buttonutilized in an emergency. By pushing the emergency stop button 31, allthe operation of the patient platform 1 can completely be stopped. Ahard-wired switch 32 is a circuit-type switch for switching statesthrough physically disconnecting or connecting wiring leads. The patientplatform controller 29 is designed in such a way that, because of thehard-wired switch 32, only when an operator grasps the patient platformoperation terminal 30, the patient platform 1 can be driven, and whenthe patient platform operation terminal 30 is released, the operation ofthe patient platform 1 stops. The lever 33, which is a JOG-drive-modeinput device, is a lever switch utilized in the JOG drive mode. Thelever 33 is a circuit-type switch for performing switching among threestates (stop, movement in a first direction, and movement in a seconddirection which is a direction opposite to the first direction) throughphysically disconnecting or connecting wiring leads. By utilizing thelevers, manipulation can be performed while the movements of the patientplatform and the patient are viewed, without viewing the patientplatform operation terminal 30; thus, the operability is enhanced andsafe operation can be performed. Reference characters 33 a, 33 b, and 33c are an X-axis JOG-drive-mode lever, a Y-axis JOG-drive-mode lever, anda Z-axis JOG-drive-mode lever, respectively. Reference characters 33 d,33 e, and 33 f are a yaw-rotating-axis JOG-drive-mode lever, arolling-rotation-axis JOG-drive-mode lever, and a pitching-rotation-axisJOG-drive-mode lever, respectively. Reference characters 33 g, 33 h, and33 i are a new-yaw-rotation JOG-drive-mode lever, a new-rolling-rotationJOG-drive-mode lever, and a new-pitching-rotation JOG-drive-mode lever,respectively. The drive modes will be explained in detail in the nextparagraph.

In the patient platform controller 29 according to Embodiment 3 of thepresent invention, the drive modes are roughly categorized into anautomatic drive mode and a JOG drive mode. In the automatic drive mode,a desired state of the patient platform is inputted, as a numericalvalue, by means of an input device such as a button switch; when thedrive start is instructed, the patient platform 1 is driving-controlledso as to be in the desired state. In contrast, in the JOG drive mode, bythrowing the JOG-drive-mode lever 33 allocated to each drive axis(driving device), the corresponding axis is driven. For example, whenthe X-axis JOG-drive-mode lever 33 a is tilted upward, the X-translationmember 3 is translated in the positive X direction; in contrast, whenthe X-axis JOG-drive-mode lever 33 a is tilted downward, theX-translation member 3 is translated in the negative X direction. Theforegoing relationship applies also to the rotation direction. Forexample, when the yaw-rotation JOG-drive-mode lever 33 d is tiltedupward, the yaw rotation member 6 is rotated in the positiveyaw-rotation direction; in contrast, when the yaw-rotationJOG-drive-mode lever 33 d is tilted downward, the yaw rotation member 6is rotated in the negative yaw-rotation direction. The input signalgenerated through the JOG-drive-mode lever 33 is inputted to thecontroller 34; while the lever 33 is connected, the controller 34outputs a control signal to the driving device of the corresponding axisso that driving is performed at a predetermined constant speed. In thisregard, however, when the input through the lever 33 exceeds the drivingrange of each axis, the controller 34 outputs an upper-limit or alower-limit control signal. As a result, the length of the connectingtime of the lever 33 a, 33 b, or 33 c determines the amount oftranslation movement; the length of the connecting time of the lever 33d, 33 e, or 33 f determines the amount of rotation movement.

The patient platform controller 29 according to Embodiment 3 of thepresent invention has a new automatic drive mode and a new JOG drivemode in addition to the foregoing automatic drive mode and the JOG drivemode. In the new automatic drive mode, when, by use of the programdescribed in Embodiment 1, a desired patient platform posture isinputted as a numerical value by means of an input device such as abutton switch and the drive start is instructed, the patient platform 1is controlled in such a way as to be yaw-rotated, rolling-rotated, andpitching-rotated on the isocenter; as a result, the patient platform 1is driving-controlled in such a way that the isocenter positions on thetop board 8 before and after the drive does not change. In the new JOGdrive mode, by use of the program described in Embodiment 1, theJOG-drive-mode lever 33 g, 33 h, and 33 i allocated to the respectiverotation drive axis (rotation driving devices) are manipulated. Whilethe lever 33 g, 33 h, or 33 i is tilted, the corresponding portion ofthe patient platform 1 is rotated on the corresponding axis at apredetermined constant angular velocity. In other words, by throwing thelever 33 g, 33 h, or 33 i, the patient platform 1 is driving-controlledin the corresponding rotation direction, as if a focused point (e.g.,isocenter) is a rotation center point. As a result, the patient platform1 is driving-controlled in such a way that the position of the focusedpoint (e.g., isocenter) on the top board 8, i.e., the desired point 22is always fixed.

Regardless of the type of a patient platform such as a bed or a chair,the patient platform controller 29 according to Embodiment 3 of thepresent invention can be applied even to an already installed patientplatform, without hardware modification or additional construction workbeing carried out. As described above, because of the scalability, adiseased site can be rotated on a desired point P in a simply andhigh-operability manner. Moreover, utilizing an isocenter as the desiredcenter point P of the rotation control, the posture of the patientplatform 1 can be JOG-driven while always keeping the isocenter on thetop board 8; therefore, there can readily be performed the positioningwork for making the position and the posture of a diseased site coincidewith those established when a treatment plan is generated. As a result,the time for preparing treatment can considerably be reduced.

The patient platform 1 provided with the patient platform controller 29according to Embodiment 3 implements a positioning method in whichrotation drive and translation drive are combined; therefore, a diseasedsite can be rotated on a desired point P in a high-operability manner.Moreover, utilizing an isocenter as the desired center point P of therotation control, the posture of the patient platform 1 can beautomatically driven or JOG-driven while always keeping the isocenter onthe top board 8; therefore, there can readily be performed thepositioning work for making the position and the posture of a diseasedsite coincide with those established when a treatment plan is generated.As a result, the time for preparing treatment can considerably bereduced.

The desired center point P for the rotation control may be determined bya program; however, the desired center point P may be changed bymanipulating a button through the patient platform operation terminal30. For example, as the desired center point P for the rotation control,in addition to the isocenter, positional information such as thelandmark for each patient is registered as a parameter in the program;the positional information items are selectively utilized.

In addition, there has been explained an example where the programdescribed in Embodiment 1 is integrated in the controller 34; however,the controller 34 may be incorporated in the patient platform operationterminal 30.

Embodiment 4

Embodiment 4 of the present invention is a patient platform providedwith a patient platform controller, which is a control device in whichthe program described in Embodiment 2 is integrated. A patient platformcontroller according to Embodiment 4 is similar to the patient platformcontroller (FIGS. 11, 12A, 12B and 12C) according to Embodiment 3. Thenew automatic drive mode and the new JOG drive mode will be explained.

In the new automatic drive mode, when, by use of the program describedin Embodiment 2, a desired patient platform posture is inputted as anumerical value by means of an input device such as a button switch andthe drive start is instructed, the patient platform 1 is controlled insuch a way as to be yaw-rotated, rolling-rotated, and pitching-rotatedon the desired rotation center point P; as a result, the patientplatform 1 is driving-controlled in such a way that the patient platform1 is rotated on a point within a predetermined distance from the desiredcenter point P. In the new JOG drive mode, by use of the programdescribed in Embodiment 2, the JOG-drive-mode lever 33 g, 33 h, and 33 iallocated to the respective rotation drive axis (rotation drivingdevices) are manipulated. By throwing the lever 33 g, 33 h, or 33 i, thepatient platform 1 is driving-controlled in such a way that the postureof the diseased site is rotated in the corresponding rotation direction,and the position of the diseased site is within a predetermined distancefrom the desired rotation center point P. Normally, the distance of apositional deviation (coordinate deviation) caused by an error in thedriving device for the patient platform 1 is short; thus, even in thecase where a positional deviation (coordinate deviation) caused by anerror in the driving device for the patient platform 1 occurs, thereexists no obstacle to the positioning work in the JOG drive mode.

As is the case with Embodiment 3, regardless of the type of a patientplatform such as a bed or a chair, the patient platform controller 29according to Embodiment 4 of the present invention can be applied evento an already installed patient platform, without hardware modificationor additional construction work being carried out. As described above,because of the scalability, the patient platform 1 can readily andautomatically be rotated on a point within a predetermined distance fromthe desired rotation center point P. Therefore, there can readily beperformed the positioning work for making the position and the postureof a diseased site coincide with those established when a treatment planis generated. As a result, the time for preparing treatment canconsiderably be reduced.

As is the case with Embodiment 3, the patient platform 1 provided withthe patient platform controller 29 according to Embodiment 4 implementsa positioning method in which rotation drive and translation drive arecombined; therefore, the posture of the diseased site can be rotatedwith high operability, and the position of the diseased site can becontrolled so as to be within a predetermined distance from the desiredrotation center point P. Because the posture of the patient platform 1can be automatically driven or JOG-driven, there can readily beperformed the positioning work for making the position and the postureof a diseased site coincide with those established when a treatment planis generated. As a result, the time for preparing treatment canconsiderably be reduced.

In the case where the driving device is controlled through automaticdrive by use of a control signal in which an offset is set, by making itpossible to change the offset by button manipulation through the patientplatform operation terminal 30, for example, in the case where adiseased site appears at the bottom of the captured image of the X-rayimage-capturing device, there can be performed with high operability theoperation in which, by rotating the posture of the diseased site on thedesired rotation center point P, the whole diseased site can be moved tothe center of the captured image. In such a way as described above, itis made possible to move the diseased site to a desired position in ashorter time than that in the case where the diseased site is moved tothe center of the captured image and then is rotated on the desiredrotation center point P.

As is the case with Embodiment 3, the desired point P for rotationcontrol may preliminarily be determined in the program; however, thedesired point P may be changed by button manipulation through thepatient platform operation terminal 30. The controller 34 may beincorporated in the patient platform operation terminal 30.

Embodiment 5

In Embodiments 1 through 4, it has been described how the rotation drivesignal and the translation drive signal for the driving type patientplatform 1, i.e., the command values of the command signals sig1 athrough sig1 f for the driving type patient platform 1 should begenerated in order to realize the rotation on the desired rotationcenter point P. In Embodiments 1 through 4, the rotation drive signaland the translation drive signal generated by the controller 34 areutilized as a feed-forward control signal. In Embodiment 5, a completelydifferent approach will be taken.

In Embodiment 5, by implementing feedback control, the foregoingproblems are solved. The method will be specifically described withreference to FIGS. 13A and 13B. A set of FIG. 13A and FIG. 13B is ablock diagram for explaining the control of the patient platform 1according to Embodiment 5. A set of FIG. 13A and FIG. 13B is differentfrom a set of FIG. 8A and FIG. 8B in Embodiment 1 in that an adjustingunit 73 (73 a) is added to the controller 34 (34 c) and the drivingdevices 35 through 40 are controlled by difference command signals sig4a through sig4 f outputted from the adjusting unit 73 (73 a). Asdescribed above, in general, a detection signal from an encoder or thelike is fed back to a motor driver, and the driver controls a motor. InEmbodiment 5 of the present invention, a detection signal from anencoder or the like is inputted to the controller 34 (34 c), and thecontroller 34 (34 c) controls a motor.

The adjusting unit 73 (73 a) of the controller 34 (34 c) compares thepresent state {x(t) through ξ(t)} (position posture) of the patientplatform 1 with the desired position and posture {x*,y*,z*,θ*,φ*,ξ} sothat the command values of the difference command signals sig4 a throughsig4 f such as the torque command and the like are generated inaccording to the difference. As a result, an effect the same as thatdemonstrated in each of Embodiments 1 through 4 can be obtained.

The adjusting unit 73 (73 a) is provided with respective feedbacksystems having transfer functions 74 a through 74 f corresponding to thedriving devices (motors) 35 through 40. Signals for realizing thedesired position and posture {x*, y*, z*, θ*, φ*, ξ*} and the detectionsignals sig3 a through sig3 f obtained by detecting the present state{x(t) through ξ(t)} of the patient platform 1 are inputted to therespective feedback systems. In this situation, in FIGS. 13A and 13B,the reference characters added to FIGS. 8A and 8B are as follows. Thetransfer function 74 a and the difference command signal sig4 a arerelated to the driving device (X translation motor) 35. The transferfunction 74 b and the difference command signal sig4 b are related tothe driving device (Y translation motor) 36. The transfer function 74 cand the difference command signal sig4 c are related to the drivingdevice (Z translation motor) 37. The transfer function 74 d and thedifference command signal sig4 d are related to the driving device (yawrotation motor) 38. The transfer function 74 e and the differencecommand signal sig4 e are related to the driving device (rollingrotation motor) 39. The transfer function 74 f and the differencecommand signal sig4 f are related to the driving device (pitchingrotation motor) 40.

It is conceivable that, in the controller 34, a dead band is set in aunit where the command value of the torque command or the like isgenerated. A set of FIG. 14A and FIG. 14B is another block diagram forexplaining the control of the patient platform 1 according to Embodiment5. A set of FIG. 14A and FIG. 14B is different from a set of FIG. 13Aand FIG. 13B in that the transfer functions in the adjusting unit 73 (73b) of the controller 34 (34 d) are transfer functions 75 a through 75 fin which dead bands are set. The P-control where a dead band is set isexpressed by the following equation. The equation (21) represents thecharacteristics of the transfer function 75 a, and it represents anexample where a dead band is provided in the P-control of the drivingdevice (X translation motor) 35.

$\begin{matrix}{{K_{x}(s)} = \left\{ \begin{matrix}K_{P} & {{{if}\mspace{14mu}{{{x(t)} - x^{*}}}} > ɛ} \\0 & {{{if}\mspace{14mu}{{{x(t)} - x^{*}}}} \leq ɛ}\end{matrix} \right.} & (21)\end{matrix}$where K_(p) is a gain, and ε is a parameter for determining thelargeness of the dead band. By providing a dead band, chattering of amotor can be prevented.

In each of the driving devices 36 through 40 other than the drivingdevice (X translation motor) 35, a dead band is provided in theP-control in the same manner as represented by the equation (21). As theequation representing the characteristics of the transfer function 75 bthat corresponds to the driving device (Y translation motor) 36, theequation obtained by replacing “x” in the equation (21) by “y” may beutilized. As the equation representing the characteristics of thetransfer function 75 c that corresponds to the driving device (Ztranslation motor) 37, the equation obtained by replacing “x” in theequation (21) by “z” may be utilized. As the equation representing thecharacteristics of the transfer function 75 d that corresponds to thedriving device (yaw rotation motor) 38, the equation obtained byreplacing “x” in the equation (21) by may be utilized. As the equationrepresenting the characteristics of the transfer function 75 e thatcorresponds to the driving device (rolling rotation motor) 39, theequation obtained by replacing “x” in the equation (21) by “φ” may beutilized. As the equation representing the characteristics of thetransfer function 75 f that corresponds to the driving device (pitchingrotation motor) 40, the equation obtained by replacing “x” in theequation (21) by “ξ” may be utilized.

The explanation for Embodiment 5 has been performed with reference to aset of FIG. 13A and FIG. 13B or a set of FIG. 14A and FIG. 14B, which isa modification of a set of FIG. 8A and FIG. 8B in Embodiment 1; thisexplanation can be applied to a modification of a set of FIG. 10A andFIG. 10B in Embodiment 2. There is utilized a controller obtained byreplacing the control of the patient platform 1 from the output unit 67in FIGS. 10A and 10B by the control of the patient platform 1 from theoutput unit 67 in a set of FIG. 13A and FIG. 13B or a set of FIG. 14Aand FIG. 14B. As a result, an effect the same as that demonstrated ineach of Embodiments 2 and 4 can be obtained.

Because of the foregoing configuration by the patient platform 1according to Embodiment 5, the program for implementing the positioningmethod for the patient platform 1, and the patient platform controller29, the driving type patient platform 1 can automatically be rotated ona point that is within a predetermined distance from the desiredrotation center point P; there can efficiently be performed thepositioning work for making the position and the posture of a diseasedsite coincide with those established when a treatment plan is generated.

Embodiment 6

In Embodiment 6, there will be described a more irregular method than inEmbodiment 5. In Embodiment 6, the posture and the position of thepatient platform 1 are separately controlled. The target posture of thepatient platform 1 is given explicitly. Accordingly, as is the case witha conventional technology, the posture of the patient platform 1 mayindependently be controlled. What matters is how to control the positionof the patient platform. The method will be described below.

The controller 34 comprehends the present actual state {x(t), y(t),z(t), θ(t), φ(t), ξ(t)} of the patient platform, based on the detectionsignals sig3 a through sig3 f from encoders or the like. In thissituation, the controller 34 has the coordinate transformation unit C2(the second coordinate transformation unit), represented by the equation(13), for performing transformation of the coordinate system from “thecoordinate system o_(obj) fixed to the top board” (moving coordinatesystem) into “the coordinate system O_(fix) fixed to the treatment room”(fixed coordinate system); therefore, it can always be calculated wherea certain position on the top board is situated in the treatment room.

The method of inputting the desired rotation center point is completelythe same as the method in each of Embodiments 1 through 5. Thecoordinates p_(a) in a moving coordinate system and the coordinatesP_(fix) in a fixed coordinate system of the desired rotation centerpoint at a time before driving (in the state “a”) are inputted to thecontroller 34. In the state “b”, instead of inputting the target postureof the patient platform, the present state is inputted.

Based on the present state {x(t), y(t), z(t), θ(t), φ(t), ξ(t)} of thepatient platform and the coordinates p_(a) of the desired rotationcenter point in the moving coordinate system at a time of the initialstate (state “a”), the controller 34 calculates the position coordinatesP_(ab) of the desired rotation center point in the fixed coordinatesystem at the present time (state “b”). Furthermore, the controller 34calculates the difference between the position coordinates of thedesired rotation center point in the fixed coordinate system at thepresent time (state “b”) and the coordinates P_(fix) in the fixedcoordinate system at the initial state (in the state “a”), andcompensates the translation drive signal for the patient platform insuch a way that the absolute value of the difference becomes the sane asor smaller than a predetermined value.

Because of the foregoing configuration by the patient platform 1according to Embodiment 6, the program for implementing the positioningmethod for the patient platform 1, and the patient platform controller29, the driving type patient platform 1 can automatically be rotated ona point that is within a predetermined distance from the desiredrotation center point P; therefore, there can efficiently be performedthe positioning work for making the position and the posture of adiseased site coincide with those established when a treatment plan isgenerated.

Embodiment 7

Embodiment 7 of the present invention is a particle beam therapy systemprovided with the patient platform 1 described in each of Embodiments 1through 6. FIG. 15 is a schematic configuration diagram illustrating aparticle beam therapy system according to Embodiment 7 of the presentinvention. A particle beam therapy system 51 includes an ion beamgeneration apparatus 52, an ion beam transport system 59, particle beamirradiation apparatuses 58 a and 58 b, and patient platforms 1 a and 1 bon which a patient is placed and fixed. The ion beam generationapparatus 52 includes an ion source (unillustrated), a prestageaccelerator 53, and a synchrotron 54. The particle beam irradiationapparatus 58 b is provided in a rotating gantry (unillustrated). Theparticle beam irradiation apparatus 58 a is provided in a treatment roomwhere no rotating gantry is installed. The function of the ion beamtransport system 59 is to achieve communication between the synchrotron54 and the particle beam irradiation apparatuses 58 a and 58 b. Aportion of the ion beam transport system 59 is provided in the rotatinggantry (unillustrated), and in that portion, there are included aplurality of deflection electromagnets 55 a, 55 b, and 55 c.

A charged particle beam, which is a particle beam such as a proton beamgenerated in ion source, is accelerated by the prestage accelerator 53and enters the synchrotron 54. The particle beam is accelerated to havepredetermined energy. The charged particle beam launched from thesynchrotron 54 is transported to the particle beam irradiationapparatuses 58 a and 58 b by way of the ion beam transport system 59.The particle beam irradiation apparatuses 58 a and 58 b each irradiatethe charged particle beam onto the irradiation subject (unillustrated)of a patient placed on the patient platform 1 a or 1 b. In FIG. 15, thepatient platform 1 a is a chair type, and the patient platform 1 b is abed type.

The particle beam therapy system 51 according to Embodiment 7 isprovided with the patient platform 1 for which there is implemented apositioning method in which rotation drive and translation drive arecombined; therefore, there can efficiently be performed the positioningwork for making the position and the posture of a diseased site coincidewith those established when a treatment plan is generated. As a result,the time for preparing treatment can considerably be reduced. Moreover,the throughput of the particle beam therapy system can be improved.

The driving type patient platform, the control device for the drivingtype patient platform, and the control program for the driving typepatient platform described in each of Embodiments 1 through 6 can beapplied not only to a particle beam therapy system but also to aradiation therapy system that irradiates an X-ray or the like.

Various modifications and alterations of this invention will be apparentto those skilled in the art without departing from the scope and spiritof this invention, and it should be understood that this is not limitedto the illustrative embodiments set forth herein.

What is claimed is:
 1. A driving type patient platform having a topboard on which an irradiation subject is fixed when a radiation isirradiated onto the irradiation subject, the driving type patientplatform comprising: a translation unit that translates the top board inthe X direction, the Y direction, and the Z direction, respectively, ina fixed coordinate system fixed to an installation place where thedriving type patient platform is installed; a rotation unit that rotatesthe top board in the θ direction around the X axis, the φ directionaround the Y axis, and the ξ direction around the Z axis, respectively;and a control device that controls the translation unit and the rotationunit, based on an inputted desired rotation center point and an inputteddesired rotation angle, wherein the control device is provided with arotation drive signal generation unit that generates a rotation drivesignal for performing rotation movement of the top board from thereference position states of the translation unit and the rotation unitto the desired rotation angle; and a translation drive signal generationunit that generates a translation drive signal for translating thetranslation unit, concurrently with performing the rotation movement, insuch a way that the amount of translation movement of the desiredrotation center point, that is caused by the rotation movement ismaintained within a predetermined value.
 2. The driving type patientplatform according to claim 1, wherein the translation drive signalgeneration unit generates a translation drive signal for translating thetranslation unit in such a way that the amount of translation movementof the desired rotation center point, that is caused by the rotationmovement is compensated.
 3. The driving type patient platform accordingto claim 2, wherein the translation drive signal generation unit isprovided with a unit that generates the coordinates (p_(a)) to beobtained by coordinate-transforming the coordinates (P_(fix)) of thedesired rotation center point in the fixed coordinate system in thereference position states into the moving coordinate system fixed to thetop board; a unit for transforming the coordinate (p_(a)) intocoordinate (P_(ab)), where coordinate (P_(ab)) is the coordinate of thepoint (p_(a)) assumed to have rotation-moved to the desired rotationangle along with the top board, expressed in the fixed coordinatesystem; and a unit that generates a translation drive signal forcompensating the moving amount of the translation unit in the respectivedirections, based on the difference between the coordinates (P_(fix))and the coordinates (P_(ab)).
 4. The driving type patient platformaccording to claim 1, wherein the control device comprises a patientplatform operation terminal for inputting, as a numerical value, thedesired rotation angle for the irradiation subject.
 5. The driving typepatient platform according to claim 1, wherein the control devicecomprises a patient platform operation terminal; and the patientplatform operation terminal comprises inputting devices eachcorresponding to the rotation axis of the rotation unit, wherein thetranslation unit and the rotation unit are driven when the correspondinginputting device is being connected.
 6. A driving type patient platformcontrol program for generating, by means of a computer, a control signalfor driving a driving type patient platform having a top board on whichan irradiation subject is fixed when a radiation is irradiated onto theirradiation subject, wherein the driving type patient platform has atranslation unit that translates the top board in the X direction, the Ydirection, and the Z direction, respectively, in a fixed coordinatesystem fixed to an installation place where the driving type patientplatform is installed; and a rotation unit that rotates the top board inthe θ direction around the X axis, the φ direction around the Y axis,and the ξ direction around the Z axis, respectively, and wherein thedriving type patient platform control program functions as a rotationdrive signal generation unit that outputs to the rotation unit arotation drive signal for performing rotation movement of the top boardfrom the reference position states of the translation unit and therotation unit to the desired rotation angle, based on an inputteddesired rotation center point and an inputted desired rotation angle,and as a translation drive signal generation unit that outputs to thetranslation unit a translation drive signal for translating thetranslation unit, concurrently with performing the rotation movement, insuch a way that the amount of translation movement, of the desiredrotation center point, that is caused by the rotation movement ismaintained within a predetermined value.
 7. The driving type patientplatform control program according to claim 6, wherein the translationdrive signal generation unit outputs to the translation unit atranslation drive signal for translating the translation unit in such away that the amount of translation movement of the desired rotationcenter point, that is caused by the rotation movement is compensated. 8.The driving type patient platform control program according to claim 7,wherein the translation drive signal generation unit implements a stepof generating the coordinates (p_(a)) to be obtained bycoordinate-transforming the coordinates (P_(fix)) of the desiredrotation center point in the fixed coordinate system in the referenceposition states into the moving coordinate system fixed to the topboard; a step of transforming the coordinate (p_(a)) into coordinate(P_(ab)), where coordinate (P_(ab)) is the coordinate of the point(p_(a)) assumed to have rotation-moved to the desired rotation anglealong with the top board, expressed in the fixed coordinate system; anda step of generating a translation drive signal for compensating themoving amounts of the translation unit in the respective directions,based on the difference between the coordinates (P_(fix)) and thecoordinates (P_(ab)).
 9. A driving type patient platform control deviceprogrammed with the driving type patient platform control programaccording to claim 6, wherein the driving type platform control devicecomprises a patient platform operation terminal for inputting, as anumerical value, the desired rotation angle for the irradiation subject.10. A driving type patient platform control device including the drivingtype patient platform control program according to claim 6, wherein thedriving type patient platform control device comprises inputting deviceseach corresponding to the rotation axis of the rotation unit, whereinthe translation unit and the rotation unit are driven when thecorresponding inputting device is being connected.
 11. A particle beamtherapy system comprising: an ion beam generation apparatus thatgenerates a charged particle beam and accelerates the charged particlebeam by means of an accelerator until the charged particle beam acquiresa predetermined energy; an ion beam transport system that transports thecharged particle beam accelerated by the ion beam generation apparatus;a particle beam irradiation apparatus that irradiates the chargedparticle beam transported by the ion beam transport system onto anirradiation subject; and a driving type patient platform having a topboard on which the irradiation subject is fixed, wherein the drivingtype patient platform is the driving type patient platform according toclaim
 1. 12. The driving type patient platform according to claim 2,wherein the control device comprises a patient platform operationterminal for inputting, as a numerical value, the desired rotation anglefor the irradiation subject.
 13. The driving type patient platformaccording to claim 2, wherein the control device comprises a patientplatform operation terminal; and the patient platform operation terminalcomprises inputting devices each corresponding to the rotation axis ofthe rotation unit, wherein the translation unit and the rotation unitare driven when the corresponding inputting device is being connected.14. The driving type patient platform according to claim 3, wherein thecontrol device comprises a patient platform operation terminal; and thepatient platform operation terminal comprises inputting devices eachcorresponding to the rotation axis of the rotation unit, wherein thetranslation unit and the rotation unit are driven when the correspondinginputting device is being connected.
 15. A driving type patient platformcontrol device including the driving type patient platform controlprogram according to claim 7, wherein the driving type patient platformcontrol device comprises inputting devices each corresponding to therotation axis of the rotation unit, wherein the translation unit and therotation unit are driven when the corresponding inputting device isbeing connected.
 16. A driving type patient platform control deviceincluding the driving type patient platform control program according toclaim 8, wherein the driving type patient platform control devicecomprises inputting devices each corresponding to the rotation axis ofthe rotation unit, wherein the translation unit and the rotation unitare driven when the corresponding inputting device is being connected.